a. (CH3CO)2O, then Sn/HCl
b. Sn/HCl, then CH3COOH
c. Sn/HCl, then (CH3CO)2O
d. CH3COOH at 180°, then Sn/HCl
e. Sn/HCl, then NaNO2/HCl, then (CH3CO)2O
3. Which sequence represents the best synthesis of 4-isopropylbenzonitrile?